Pepper: Add support for multicast in PPB_UDPSocket API

ppapi/cpp/udp_socket.h

Index: ppapi/cpp/udp_socket.h
diff --git a/ppapi/cpp/udp_socket.h b/ppapi/cpp/udp_socket.h
index 707c62102a17318c45c44b2672f8697b33701c9f..69e906ff20919ddb226029dcf80792a89cad18c4 100644
--- a/ppapi/cpp/udp_socket.h
+++ b/ppapi/cpp/udp_socket.h
@@ -156,6 +156,30 @@ class UDPSocket : public Resource {
   int32_t SetOption(PP_UDPSocket_Option name,
                     const Var& value,
                     const CompletionCallback& callback);
+
+  /// Joins the multicast group with address specified by <code>group</code>
+  /// parameter, which is expected to be a <code>NetAddress</code> object.
+  ///
+  /// @param[in] group A <code>NetAddress</code> corresponding to the network
+  /// address of the multicast group.
+  /// @param[in] callback A <code>CompletionCallback</code> to be called upon
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  int32_t JoinGroup(const NetAddress& group,
+                    const CompletionCallback callback);
+
+  /// Leaves the multicast group with address specified by <code>group</code>
+  /// parameter, which is expected to be a <code>NetAddress</code> object.
+  ///
+  /// @param[in] group A <code>NetAddress</code> corresponding to the network
+  /// address of the multicast group.
+  /// @param[in] callback A <code>CompletionCallback</code> to be called upon
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  int32_t LeaveGroup(const NetAddress& group,
+                     const CompletionCallback callback);
 };
 
 }  // namespace pp